1. Field of the Invention
The present invention relates to an image processing device, and more particularly, to an image processing device selecting a loading circuit among a plurality of loading circuits according to a speed of a first module.
2. Description of the Prior Art
Image processing devices, such as computer printing devices, photocopiers, scanners and multi-functional peripherals (MFP) are broadly applied nowadays. The request of the resolution of the scanning modules of the image processing devices is increasing, and the choices of resolutions are various. The speed of the motor pushing the scanning module of the scanner or the multi-functional peripheral may be decided according to the resolution of scanning and the amount of data to be scanned.
Please refer to FIG. 1. FIG. 1 is a block diagram of a prior art image processing device. 100 is a conventional image processing device, which may be a multi-functional peripheral or a scanner. 110 is a scanning module of the image processing device 100. 120 is a motor system electrically connected to the scanning module 110 and capable of pushing the scanning module 110 to move forward. The motor system 120 includes a power supply 122, a loading circuit 124, a motor 126 and a driver 128, wherein the driver 128 is utilized to drive the motor 126. 130 is a controller electrically connected to the driver 128 and capable of controlling a speed of the motor 126 pushing the scanning module 110 forward. For example, when the image processing device 100 of the prior art scans the document with a low resolution, the motor 126 pushes the scanning module 110 to move forward at a higher speed for the amount of data is small. The controller 130 accordingly commands the driver 128 to control the motor 126 pushing the scanning module 110 to move forward at a high speed. When scanning documents with a high resolution, the motor 126 needs to push the scanning module 110 to move forward at a low speed for the amount of data is large. The controller 130 accordingly commands the driver 128 to control the motor 126 pushing the scanning module 110 to move forward slowly. Furthermore, when the multi-functional peripheral is switched to copy mode, the speed of the motor is set in accordance with the speed of the printing module. When copying with a low resolution, for example, printing documents in a sketch mode, the scanning module scans faster because fewer data is extracted. Accordingly, the speed of the motor may be faster. On the contrary, when copying with a higher resolution, for example, when printing photos, the scanning module scans faster because the amount of extracted data is huge. Accordingly, the speed of the motor should be higher. When scanning slowly, the motor does not need much power to push the scanning module. Contrarily, when scanning fast, the motor needs more power to maintain the operation of the system. However, in the conventional image processing device 100, the loading circuit by which the motor system 120 controls the power provided by the power supply 122 to the motor 126 is fixed to the loading circuit 124. Accordingly, the input power of the motor system has to be designed to meet the requirement of the mode of the highest scanning speed, that is, to meet the maximum required power. That means, the loading circuit 124 is designed to make the power provided by the power supply 122 to the motor 126 a maximum power that is ever needed. However, when the motor system scans documents at a lower speed, there will be excess power. The excess power will be transferred into heat and makes the motor hot, which damages the motor system gradually and easily.